1 /*
2 * Copyright (c) 1996, 2013, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation. Oracle designates this
8 * particular file as subject to the "Classpath" exception as provided
9 * by Oracle in the LICENSE file that accompanied this code.
10 *
11 * This code is distributed in the hope that it will be useful, but WITHOUT
12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
14 * version 2 for more details (a copy is included in the LICENSE file that
15 * accompanied this code).
16 *
17 * You should have received a copy of the GNU General Public License version
18 * 2 along with this work; if not, write to the Free Software Foundation,
19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20 *
21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
22 * or visit www.oracle.com if you need additional information or have any
23 * questions.
24 */
25
26 package java.lang.reflect;
27
28 import jdk.internal.misc.SharedSecrets;
29 import jdk.internal.reflect.CallerSensitive;
30 import jdk.internal.reflect.ConstructorAccessor;
31 import jdk.internal.reflect.Reflection;
32 import jdk.internal.vm.annotation.ForceInline;
33 import sun.reflect.annotation.TypeAnnotation;
34 import sun.reflect.annotation.TypeAnnotationParser;
35 import sun.reflect.generics.repository.ConstructorRepository;
36 import sun.reflect.generics.factory.CoreReflectionFactory;
37 import sun.reflect.generics.factory.GenericsFactory;
38 import sun.reflect.generics.scope.ConstructorScope;
39 import java.lang.annotation.Annotation;
40 import java.lang.annotation.AnnotationFormatError;
41
42 /**
43 * {@code Constructor} provides information about, and access to, a single
44 * constructor for a class.
45 *
46 * <p>{@code Constructor} permits widening conversions to occur when matching the
47 * actual parameters to newInstance() with the underlying
48 * constructor's formal parameters, but throws an
49 * {@code IllegalArgumentException} if a narrowing conversion would occur.
50 *
51 * @param <T> the class in which the constructor is declared
52 *
53 * @see Member
54 * @see java.lang.Class
55 * @see java.lang.Class#getConstructors()
56 * @see java.lang.Class#getConstructor(Class[])
57 * @see java.lang.Class#getDeclaredConstructors()
58 *
59 * @author Kenneth Russell
60 * @author Nakul Saraiya
61 */
62 public final class Constructor<T> extends Executable {
63 private Class<T> clazz;
64 private int slot;
65 private Class<?>[] parameterTypes;
66 private Class<?>[] exceptionTypes;
67 private int modifiers;
68 // Generics and annotations support
69 private transient String signature;
70 // generic info repository; lazily initialized
71 private transient ConstructorRepository genericInfo;
72 private byte[] annotations;
73 private byte[] parameterAnnotations;
74
75 // Generics infrastructure
76 // Accessor for factory
77 private GenericsFactory getFactory() {
78 // create scope and factory
79 return CoreReflectionFactory.make(this, ConstructorScope.make(this));
80 }
81
82 // Accessor for generic info repository
83 @Override
84 ConstructorRepository getGenericInfo() {
85 // lazily initialize repository if necessary
86 if (genericInfo == null) {
87 // create and cache generic info repository
88 genericInfo =
89 ConstructorRepository.make(getSignature(),
90 getFactory());
91 }
92 return genericInfo; //return cached repository
93 }
94
95 private volatile ConstructorAccessor constructorAccessor;
96 // For sharing of ConstructorAccessors. This branching structure
97 // is currently only two levels deep (i.e., one root Constructor
98 // and potentially many Constructor objects pointing to it.)
99 //
100 // If this branching structure would ever contain cycles, deadlocks can
101 // occur in annotation code.
102 private Constructor<T> root;
103
104 /**
105 * Used by Excecutable for annotation sharing.
106 */
107 @Override
108 Executable getRoot() {
109 return root;
110 }
111
112 /**
113 * Package-private constructor used by ReflectAccess to enable
114 * instantiation of these objects in Java code from the java.lang
115 * package via sun.reflect.LangReflectAccess.
116 */
117 Constructor(Class<T> declaringClass,
118 Class<?>[] parameterTypes,
119 Class<?>[] checkedExceptions,
120 int modifiers,
121 int slot,
122 String signature,
123 byte[] annotations,
124 byte[] parameterAnnotations) {
125 this.clazz = declaringClass;
126 this.parameterTypes = parameterTypes;
127 this.exceptionTypes = checkedExceptions;
128 this.modifiers = modifiers;
129 this.slot = slot;
130 this.signature = signature;
131 this.annotations = annotations;
132 this.parameterAnnotations = parameterAnnotations;
133 }
134
135 /**
136 * Package-private routine (exposed to java.lang.Class via
137 * ReflectAccess) which returns a copy of this Constructor. The copy's
138 * "root" field points to this Constructor.
139 */
140 Constructor<T> copy() {
141 // This routine enables sharing of ConstructorAccessor objects
142 // among Constructor objects which refer to the same underlying
143 // method in the VM. (All of this contortion is only necessary
144 // because of the "accessibility" bit in AccessibleObject,
145 // which implicitly requires that new java.lang.reflect
146 // objects be fabricated for each reflective call on Class
147 // objects.)
148 if (this.root != null)
149 throw new IllegalArgumentException("Can not copy a non-root Constructor");
150
151 Constructor<T> res = new Constructor<>(clazz,
152 parameterTypes,
153 exceptionTypes, modifiers, slot,
154 signature,
155 annotations,
156 parameterAnnotations);
157 res.root = this;
158 // Might as well eagerly propagate this if already present
159 res.constructorAccessor = constructorAccessor;
160 return res;
161 }
162
163 /**
164 * {@inheritDoc}
165 *
166 * <p> A {@code SecurityException} is also thrown if this object is a
167 * {@code Constructor} object for the class {@code Class} and {@code flag}
168 * is true. </p>
169 *
170 * @param flag {@inheritDoc}
171 */
172 @Override
173 @CallerSensitive
174 public void setAccessible(boolean flag) {
175 AccessibleObject.checkPermission();
176 if (flag) {
177 checkCanSetAccessible(Reflection.getCallerClass());
178 }
179 setAccessible0(flag);
180 }
181
182 @Override
183 void checkCanSetAccessible(Class<?> caller) {
184 checkCanSetAccessible(caller, clazz);
185 if (clazz == Class.class) {
186 // can we change this to InaccessibleObjectException?
187 throw new SecurityException("Cannot make a java.lang.Class"
188 + " constructor accessible");
189 }
190 }
191
192 @Override
193 boolean hasGenericInformation() {
194 return (getSignature() != null);
195 }
196
197 @Override
198 byte[] getAnnotationBytes() {
199 return annotations;
200 }
201
202 /**
203 * {@inheritDoc}
204 */
205 @Override
206 public Class<T> getDeclaringClass() {
207 return clazz;
208 }
209
210 /**
211 * Returns the name of this constructor, as a string. This is
212 * the binary name of the constructor's declaring class.
213 */
214 @Override
215 public String getName() {
216 return getDeclaringClass().getName();
217 }
218
219 /**
220 * {@inheritDoc}
221 */
222 @Override
223 public int getModifiers() {
224 return modifiers;
225 }
226
227 /**
228 * {@inheritDoc}
229 * @throws GenericSignatureFormatError {@inheritDoc}
230 * @since 1.5
231 */
232 @Override
233 @SuppressWarnings({"rawtypes", "unchecked"})
234 public TypeVariable<Constructor<T>>[] getTypeParameters() {
235 if (getSignature() != null) {
236 return (TypeVariable<Constructor<T>>[])getGenericInfo().getTypeParameters();
237 } else
238 return (TypeVariable<Constructor<T>>[])new TypeVariable[0];
239 }
240
241
242 /**
243 * {@inheritDoc}
244 */
245 @Override
246 public Class<?>[] getParameterTypes() {
247 return parameterTypes.clone();
248 }
249
250 /**
251 * {@inheritDoc}
252 * @since 1.8
253 */
254 public int getParameterCount() { return parameterTypes.length; }
255
256 /**
257 * {@inheritDoc}
258 * @throws GenericSignatureFormatError {@inheritDoc}
259 * @throws TypeNotPresentException {@inheritDoc}
260 * @throws MalformedParameterizedTypeException {@inheritDoc}
261 * @since 1.5
262 */
263 @Override
264 public Type[] getGenericParameterTypes() {
265 return super.getGenericParameterTypes();
266 }
267
268 /**
269 * {@inheritDoc}
270 */
271 @Override
272 public Class<?>[] getExceptionTypes() {
273 return exceptionTypes.clone();
274 }
275
276
277 /**
278 * {@inheritDoc}
279 * @throws GenericSignatureFormatError {@inheritDoc}
280 * @throws TypeNotPresentException {@inheritDoc}
281 * @throws MalformedParameterizedTypeException {@inheritDoc}
282 * @since 1.5
283 */
284 @Override
285 public Type[] getGenericExceptionTypes() {
286 return super.getGenericExceptionTypes();
287 }
288
289 /**
290 * Compares this {@code Constructor} against the specified object.
291 * Returns true if the objects are the same. Two {@code Constructor} objects are
292 * the same if they were declared by the same class and have the
293 * same formal parameter types.
294 */
295 public boolean equals(Object obj) {
296 if (obj != null && obj instanceof Constructor) {
297 Constructor<?> other = (Constructor<?>)obj;
298 if (getDeclaringClass() == other.getDeclaringClass()) {
299 return equalParamTypes(parameterTypes, other.parameterTypes);
300 }
301 }
302 return false;
303 }
304
305 /**
306 * Returns a hashcode for this {@code Constructor}. The hashcode is
307 * the same as the hashcode for the underlying constructor's
308 * declaring class name.
309 */
310 public int hashCode() {
311 return getDeclaringClass().getName().hashCode();
312 }
313
314 /**
315 * Returns a string describing this {@code Constructor}. The string is
316 * formatted as the constructor access modifiers, if any,
317 * followed by the fully-qualified name of the declaring class,
318 * followed by a parenthesized, comma-separated list of the
319 * constructor's formal parameter types. For example:
320 * <pre>{@code
321 * public java.util.Hashtable(int,float)
322 * }</pre>
323 *
324 * <p>The only possible modifiers for constructors are the access
325 * modifiers {@code public}, {@code protected} or
326 * {@code private}. Only one of these may appear, or none if the
327 * constructor has default (package) access.
328 *
329 * @return a string describing this {@code Constructor}
330 * @jls 8.8.3 Constructor Modifiers
331 * @jls 8.9.2 Enum Body Declarations
332 */
333 public String toString() {
334 return sharedToString(Modifier.constructorModifiers(),
335 false,
336 parameterTypes,
337 exceptionTypes);
338 }
339
340 @Override
341 void specificToStringHeader(StringBuilder sb) {
342 sb.append(getDeclaringClass().getTypeName());
343 }
344
345 /**
346 * Returns a string describing this {@code Constructor},
347 * including type parameters. The string is formatted as the
348 * constructor access modifiers, if any, followed by an
349 * angle-bracketed comma separated list of the constructor's type
350 * parameters, if any, followed by the fully-qualified name of the
351 * declaring class, followed by a parenthesized, comma-separated
352 * list of the constructor's generic formal parameter types.
353 *
354 * If this constructor was declared to take a variable number of
355 * arguments, instead of denoting the last parameter as
356 * "<code><i>Type</i>[]</code>", it is denoted as
357 * "<code><i>Type</i>...</code>".
358 *
359 * A space is used to separate access modifiers from one another
360 * and from the type parameters or return type. If there are no
361 * type parameters, the type parameter list is elided; if the type
362 * parameter list is present, a space separates the list from the
363 * class name. If the constructor is declared to throw
364 * exceptions, the parameter list is followed by a space, followed
365 * by the word "{@code throws}" followed by a
366 * comma-separated list of the thrown exception types.
367 *
368 * <p>The only possible modifiers for constructors are the access
369 * modifiers {@code public}, {@code protected} or
370 * {@code private}. Only one of these may appear, or none if the
371 * constructor has default (package) access.
372 *
373 * @return a string describing this {@code Constructor},
374 * include type parameters
375 *
376 * @since 1.5
377 * @jls 8.8.3 Constructor Modifiers
378 * @jls 8.9.2 Enum Body Declarations
379 */
380 @Override
381 public String toGenericString() {
382 return sharedToGenericString(Modifier.constructorModifiers(), false);
383 }
384
385 @Override
386 void specificToGenericStringHeader(StringBuilder sb) {
387 specificToStringHeader(sb);
388 }
389
390 /**
391 * Uses the constructor represented by this {@code Constructor} object to
392 * create and initialize a new instance of the constructor's
393 * declaring class, with the specified initialization parameters.
394 * Individual parameters are automatically unwrapped to match
395 * primitive formal parameters, and both primitive and reference
396 * parameters are subject to method invocation conversions as necessary.
397 *
398 * <p>If the number of formal parameters required by the underlying constructor
399 * is 0, the supplied {@code initargs} array may be of length 0 or null.
400 *
401 * <p>If the constructor's declaring class is an inner class in a
402 * non-static context, the first argument to the constructor needs
403 * to be the enclosing instance; see section 15.9.3 of
404 * <cite>The Java™ Language Specification</cite>.
405 *
406 * <p>If the required access and argument checks succeed and the
407 * instantiation will proceed, the constructor's declaring class
408 * is initialized if it has not already been initialized.
409 *
410 * <p>If the constructor completes normally, returns the newly
411 * created and initialized instance.
412 *
413 * @param initargs array of objects to be passed as arguments to
414 * the constructor call; values of primitive types are wrapped in
415 * a wrapper object of the appropriate type (e.g. a {@code float}
416 * in a {@link java.lang.Float Float})
417 *
418 * @return a new object created by calling the constructor
419 * this object represents
420 *
421 * @exception IllegalAccessException if this {@code Constructor} object
422 * is enforcing Java language access control and the underlying
423 * constructor is inaccessible.
424 * @exception IllegalArgumentException if the number of actual
425 * and formal parameters differ; if an unwrapping
426 * conversion for primitive arguments fails; or if,
427 * after possible unwrapping, a parameter value
428 * cannot be converted to the corresponding formal
429 * parameter type by a method invocation conversion; if
430 * this constructor pertains to an enum type.
431 * @exception InstantiationException if the class that declares the
432 * underlying constructor represents an abstract class.
433 * @exception InvocationTargetException if the underlying constructor
434 * throws an exception.
435 * @exception ExceptionInInitializerError if the initialization provoked
436 * by this method fails.
437 */
438 @CallerSensitive
439 @ForceInline // to ensure Reflection.getCallerClass optimization
440 public T newInstance(Object ... initargs)
441 throws InstantiationException, IllegalAccessException,
442 IllegalArgumentException, InvocationTargetException
443 {
444 if (!override) {
445 Class<?> caller = Reflection.getCallerClass();
446 checkAccess(caller, clazz, clazz, modifiers);
447 }
448 if ((clazz.getModifiers() & Modifier.ENUM) != 0)
449 throw new IllegalArgumentException("Cannot reflectively create enum objects");
450 ConstructorAccessor ca = constructorAccessor; // read volatile
451 if (ca == null) {
452 ca = acquireConstructorAccessor();
453 }
454 @SuppressWarnings("unchecked")
455 T inst = (T) ca.newInstance(initargs);
456 return inst;
457 }
458
459 /**
460 * {@inheritDoc}
461 * @since 1.5
462 */
463 @Override
464 public boolean isVarArgs() {
465 return super.isVarArgs();
466 }
467
468 /**
469 * {@inheritDoc}
470 * @jls 13.1 The Form of a Binary
471 * @since 1.5
472 */
473 @Override
474 public boolean isSynthetic() {
475 return super.isSynthetic();
476 }
477
478 // NOTE that there is no synchronization used here. It is correct
479 // (though not efficient) to generate more than one
480 // ConstructorAccessor for a given Constructor. However, avoiding
481 // synchronization will probably make the implementation more
482 // scalable.
483 private ConstructorAccessor acquireConstructorAccessor() {
484 // First check to see if one has been created yet, and take it
485 // if so.
486 ConstructorAccessor tmp = null;
487 if (root != null) tmp = root.getConstructorAccessor();
488 if (tmp != null) {
489 constructorAccessor = tmp;
490 } else {
491 // Otherwise fabricate one and propagate it up to the root
492 tmp = reflectionFactory.newConstructorAccessor(this);
493 setConstructorAccessor(tmp);
494 }
495
496 return tmp;
497 }
498
499 // Returns ConstructorAccessor for this Constructor object, not
500 // looking up the chain to the root
501 ConstructorAccessor getConstructorAccessor() {
502 return constructorAccessor;
503 }
504
505 // Sets the ConstructorAccessor for this Constructor object and
506 // (recursively) its root
507 void setConstructorAccessor(ConstructorAccessor accessor) {
508 constructorAccessor = accessor;
509 // Propagate up
510 if (root != null) {
511 root.setConstructorAccessor(accessor);
512 }
513 }
514
515 int getSlot() {
516 return slot;
517 }
518
519 String getSignature() {
520 return signature;
521 }
522
523 byte[] getRawAnnotations() {
524 return annotations;
525 }
526
527 byte[] getRawParameterAnnotations() {
528 return parameterAnnotations;
529 }
530
531
532 /**
533 * {@inheritDoc}
534 * @throws NullPointerException {@inheritDoc}
535 * @since 1.5
536 */
537 public <T extends Annotation> T getAnnotation(Class<T> annotationClass) {
538 return super.getAnnotation(annotationClass);
539 }
540
541 /**
542 * {@inheritDoc}
543 * @since 1.5
544 */
545 public Annotation[] getDeclaredAnnotations() {
546 return super.getDeclaredAnnotations();
547 }
548
549 /**
550 * {@inheritDoc}
551 * @since 1.5
552 */
553 @Override
554 public Annotation[][] getParameterAnnotations() {
555 return sharedGetParameterAnnotations(parameterTypes, parameterAnnotations);
556 }
557
558 @Override
559 void handleParameterNumberMismatch(int resultLength, int numParameters) {
560 Class<?> declaringClass = getDeclaringClass();
561 if (declaringClass.isEnum() ||
562 declaringClass.isAnonymousClass() ||
563 declaringClass.isLocalClass() )
564 return ; // Can't do reliable parameter counting
565 else {
566 if (!declaringClass.isMemberClass() || // top-level
567 // Check for the enclosing instance parameter for
568 // non-static member classes
569 (declaringClass.isMemberClass() &&
570 ((declaringClass.getModifiers() & Modifier.STATIC) == 0) &&
571 resultLength + 1 != numParameters) ) {
572 throw new AnnotationFormatError(
573 "Parameter annotations don't match number of parameters");
574 }
575 }
576 }
577
578 /**
579 * {@inheritDoc}
580 * @since 1.8
581 */
582 @Override
583 public AnnotatedType getAnnotatedReturnType() {
584 return getAnnotatedReturnType0(getDeclaringClass());
585 }
586
587 /**
588 * {@inheritDoc}
589 * @since 1.8
590 */
591 @Override
592 public AnnotatedType getAnnotatedReceiverType() {
593 Class<?> thisDeclClass = getDeclaringClass();
594 Class<?> enclosingClass = thisDeclClass.getEnclosingClass();
595
596 if (enclosingClass == null) {
597 // A Constructor for a top-level class
598 return null;
599 }
600
601 Class<?> outerDeclaringClass = thisDeclClass.getDeclaringClass();
602 if (outerDeclaringClass == null) {
603 // A constructor for a local or anonymous class
604 return null;
605 }
606
607 // Either static nested or inner class
608 if (Modifier.isStatic(thisDeclClass.getModifiers())) {
609 // static nested
610 return null;
611 }
612
613 // A Constructor for an inner class
614 return TypeAnnotationParser.buildAnnotatedType(getTypeAnnotationBytes0(),
615 SharedSecrets.getJavaLangAccess().
616 getConstantPool(thisDeclClass),
617 this,
618 thisDeclClass,
619 enclosingClass,
620 TypeAnnotation.TypeAnnotationTarget.METHOD_RECEIVER);
621 }
622 }